Air or oil sealing is often required between two opposing shafts such as is found in gas turbine engines. Sometimes, there is very little axial room in the available space to package and locate radial intershaft seals such as labyrinth seals.
Thus, there continues to be a need for air and oil intershaft seals which provide lighter weight seal assemblies that occupy smaller volumes with less leakage than labyrinth seals and other conventional seals. It is desirable to provide intershaft sealing in a tight design space that would otherwise require a less desirable seal such as a labyrinth seal between concentric shafts.